Generally speaking, 3D sensing based on structured light projection of a pattern in conjunction with an imaging sensor may provide non-contact 3D surface measurements of an object or shape. In some embodiments the image sensor may be a camera. In other embodiments, the image sensor may be a scanner. Many publications on the subject have been produced describing a variety of patterns spatially and/or temporally coded, in order to achieve 3D scanning. Good motion tolerance may be relatively important for handheld 3D scanners so spatially coded patterns are typically used. The methods also need to accommodate the impact of the disparity between the camera and the light projection due to the parallax distance between the camera and light projector.
Commonly employed patterns are “pseudo random” dot patterns (such as that used by the Microsoft Kinect and others) or “column coded” patterns like the one described by Vuylsteke & Oosterlinck in 1990, which is based on a chessboard pattern with diagonal connection/disconnections to encode a column index. However, these patterns may lack the performance and accuracy desired in object measurements for industrial applications.
Therefore, a need exists to improve the quality of measurements of a 3D sensing system.